1. Field of the Invention
This invention relates to digital recording/reproducing systems. More particularly, the invention relates to a system which records or reproduces digital television broadcast utilizing, for example, CS (Communication Satellite), BS (Broadcasting Satellite) or ground waves onto or from a digital recording medium, such as a DVD-RAM, MO disc or hard disc.
2. Description of the Related Art
Recently, in analog television broadcast utilizing ground waves, television signals can be recorded to and reproduced from a VTR or the like. Meanwhile, there are cases that a pay television signal, such as of CATV, is applied with copy protection. For example, the position of a horizontal synchronizing signal is changed so as not to be brought into synchronization by using a usual television receiver or VTR. In this case, video recording is impossible to perform. Furthermore, the rental videos, for example, are generally processed with Macrovision Company""s copy guard. They accordingly can be reproduced by a VTR. However, if a VTR-reproduced video image is tried to be recorded again, the video image will go out of order and is impossible to look and listen to.
Meanwhile, perfecTV, DirecTV, JskyB and so on (all service marks) have inaugurated their digital broadcast services utilizing communication satellites (CS). In these of digital television broadcast, the Macrovision""s copy guards are applied to unrecordable programs. As for the recordable program, if a fee higher than the usual subscription rate is paid, such program can be recorded as an analog television signal. In such a case, it is possible to carry out dubbing with the recorded video tape. Such dubbing, if performed for purposes other than personal enjoyment, would result in violation against the Copyright law. Such dubbing may financially damage the broadcaster.
Also, copy guard systems have being introduced to an application of the DVD (Digital Video Disc) recorded with a movie or the like. In DVD, the video signal is compressed according to MPEG, similarly to digital television broadcast. The DVD reproducer decompresses the compressed video signal and converts it into an analog television signal, being supplied through a connection terminal to the television receiver. The analog television signal output through the connection terminal is processed with Macrovision""s copy guard.
In both the broadcast media and the storage media, measures are taken such that the digital television signal cannot be copied for the purpose of protecting copyright.
Incidentally, in Japanese Patent Laid-open No. 214929/1997 (Billing System Apparatus) [HO4N 7/16, 5/91], billing is implemented in accordance with a program during reproducing/dubbing with a VTR-recorded pay-program television signal, wherein an STB (Set Top Box) received signal is multiplexed with a pay-program code and further processed with copy protection in order to prevent against unpaid dubbing, thus being supplied to the VTR. The VTR releases the copy protection to perform scrambled recording. Also, in reproduction, a reproduced signal is descrambled and processed for copy protection by the VTR, thus being supplied in a pay-program encoded form to the STB. There is a proposal that a billing-implementation signal is outputted from the STB to the VTR wherein descrambling is effected only in a (viewing) duration of outputting such a billing-implementation signal. This method enables billing to occur not only during recording but also in reproducing.
Furthermore, in Japanese Patent Laid-open No. 231440/1995 (View Billing System) [HO4N/ 7/16, 7/167], a billing system for a chargeable broadcast attempts to receive a scramble broadcast and descrambles it by means of an exclusive decoder in order to view and listen. This prior art carries out billing on a particular time period basis excepting the titles descrambled in overlap, for a purpose of performing billing (possible by a recording/producing means such as VTR and special reproduction) for each of viewed programs. The identification information for the program billed is sent to a center. This information is stored on the viewer""s side, and updated (erased or added in a specified time) as required. Or otherwise, the billed-program information is stored and updated in the center without store by the viewer. According to the second prior art reference, the scrambled data, the release signal and the program identification information are digitally recorded and, upon reproduction, corrected into the before-record information form. Meanwhile, where no program identification information is inputted together with scramble data, descrambling is not carried out.
In the case of the first prior art reference, the copy-source media and the copy-destination media are the same. That is, this art is effective for a case of billing per viewing time, i.e., PPV (Pay Per View). However, in the case of title billing to effect billing during recording to enable viewing and listening after that time in a free fashion, it can be considered that the information to be recorded has not been scrambled. In such a case, it is possible to carry out illegal copying.
That is, in the both of the prior art references, billing systems have been proposed to digitally record and reproduce digital broadcast to or from a digital VTR, etc., to carry out billing. With these prior art references, it is possible to copy into a same tape form or the like. Also, billing is possible on a viewing time basis.
However, these prior art references could not be used in a service of title selling over, i.e., wherein a fee is paid upon recording a broadcast television signal and thereafter the recorded signal is utilizable exclusive for reproduction, such as in DVD or VIDEO-CD. Also, in these prior art references, copying could not be implemented because the DVD or the like was impossible to copy.
Therefore, it is a primary object of this invention to provide a novel digital recording/reproducing system.
It is another object of this invention to provide a novel billing system in digital video recording.
It is another object of this invention to provide a billing system which is capable of digitally recording a digital video image legally onto a rewritable-type recording device.
It is another object of this invention to provide a billing system which is capable of effectively effects billing when duplicating a digital video image.
A digital recording system according to the present invention has a digital data output apparatus to output scrambled digital data and a digital recording apparatus, to record the digital data to a digital recording medium, wherein the digital recording medium includes previously recorded unique identification data, the digital recording system comprising: a reading means for reading the unique identification data out of the data recording medium; a key data creating means for creating key data based on the unique identification data and a descramble key; a recording means for recording the scrambled digital data and the key data to the digital recording medium; a first approval getting means for getting an approval from a user on a billing for digital recording; an account table creating means for creating an account table depending upon an approval of the billing by the user; and a register means for registering the account table.
That is, when the user approves the billing for digital recording, a descramble key is provided. Based on this descramble key and unique identification data, key data is created. The scrambled digital data and this key data are recorded in the digital recording medium. According to the user""s approval on the billing, an account table is created which is registered, for example, in an IC card and transmitted to a center.
A digital recording system according to the present invention has a digital data output apparatus to output scrambled digital data and a digital recording apparatus, to record the digital data in a digital recording medium, wherein the digital recording medium includes previously recorded unique identification data, the digital recording system comprising: a reading means for reading the unique identification data out of the data recording medium; a first key creating means for creating a first key based on the unique identification data; a second key creating means for creating a second key based on the first key and a descramble key; a recording means for recording the scrambled digital data and the second key to the digital recording medium; a first approval getting means for getting from a user an approval of a billing for digital recording; an account table creating means for creating an account table depending upon a billing approval by the user; and a register means for registering the billing table.
That is, when the user approves the billing for digital recording, a descramble key is provided. Based on this descramble key and unique identification data, key data is created. The scrambled digital data and the second key are recorded in the digital recording medium. According to the user""s approval on the billing, an account table is created which is registered, for example, in an IC card and transmitted to a center.
A digital reproducing system according to the present invention is for reproducing scrambled digital data out of a digital recording medium, wherein the digital recording medium includes previously recorded unique identification data and key data, the digital reproducing system comprising: a reading means for reading the unique identification data out of the data recording medium; a first key creating means for creating a first key based on the unique identification data; a restoring means for restoring unique identification data based on the key data and the first key; a determining means for determining whether or not there is coincidence between unique identification data read by the reading means and unique identification data restored by the restoring means; and an allowing means for allowing reproduction of the digital data when a coincidence is determined by the determining means.
Furthermore, a method for reproducing digital data out of a digital recording medium wherein scrambled digital data and key data are recorded on the digital recording medium having unique identification data previously recorded, the digital data reproducing method comprising: (a) reading the unique identification data out of the data recording medium; (b) creating a first key based on the unique identification data; (c) restoring unique identification data based on the key data and the first key; (d) determining whether or not the read unique identification data and the restored identification data are coincident with; and (e) allowing reproduction of the
In the digitally reproducing method or system, reproduction is made from a digital recording medium previously recorded with unique identification data. This digital recording medium is recorded with scrambled digital data and key data. If there is coincidence between unique identification data read out of the digital recording medium and unique identification data restored, or between contents keys in the embodiment, the scrambled digital data is allowed to be reproduced. In this case, a descramble key can be restored from the contents key. If the two unique identification data (contents keys) are not coincident, reproduction is prohibited unless the user approve the billing.
According to this invention, billing is effectively implemented when recording or reproducing from the digital data reproduced from a digital television broadcast or digital recording medium, making possible legal copying of digital data.